As one of drive methods of a liquid crystal display device, there is conventionally known a method (hereinafter, “pixel division method”) of “configuring one pixel by a plurality of (typically two) sub pixels, and driving a liquid crystal such that brightness of the plurality of sub pixels becomes mutually different brightness”. This pixel division method is a method employed to improve a viewing angle characteristic of the liquid crystal display device.
FIG. 49 is a diagram schematically showing an example of a circuit configuration of a conventional liquid crystal display device that employs a pixel division method. As shown in FIG. 49, a pixel formation portion 93 forming one pixel is configured by two sub-pixel portions (a first sub-pixel portion 94 and a second sub-pixel portion 95). Both of the sub-pixel portions (94, 95) include transistors (T1, T2) having gate electrodes connected to a scanning signal line GL and having source electrodes connected to a data signal line SL; pixel electrodes (E1, E2) connected to drain electrodes of the transistors (T1, T2); liquid crystal capacitances (Clc1, Clc2) formed by a common electrode 41 to which a constant potential COM is provided as a counter electrode and the pixel electrodes (E1, E2); and holding capacitances (Ccs1, Ccs2) formed by the pixel electrodes (E1, E2) and holding capacitance lines (CS1, CS2). In this configuration, when the scanning signal line GL becomes in a selection state, the transistors T1, T2 become in an on state. Since the source electrode of the transistor T1 and the source electrode of the transistor T2 are connected to the same data signal line SL, a potential of the pixel electrode E1 in the first sub-pixel portion 94 and a potential of the pixel electrode E2 in the second sub-pixel portion 95 become equal. Thereafter, when a potential of one of the holding capacitance lines CS1, CS2 is increased and when a potential of the other holding capacitance line is decreased, the potential of the pixel electrode E1 and the potential of the pixel electrode E2 vary in mutually opposite directions. As a result, the potential of the pixel electrode E1 and the potential of the pixel electrode E2 become mutually different, and brightness of the first sub-pixel portion 94 and brightness of the second sub-pixel portion 95 become mutually different.
FIG. 50 is an equivalent circuit diagram of another conventional liquid crystal display device that employs a pixel division method. As shown in FIG. 50, in this liquid crystal display device, a pixel formation portion 96 is also configured by two sub-pixel portions (a first sub-pixel portion 97 and a second sub-pixel portion 98). Both of the sub-pixel portions (97, 98) include the transistors (T1, T2), the pixel electrodes (E1, E2), the liquid crystal capacitances (Clc1, Clc2), and the holding capacitances (Ccs1, Ccs2), as common constituent elements, in a similar manner to that of the example shown in FIG. 49. In this case, the second sub-pixel portion 98 further includes a transistor T3 having a gate electrode connected to a second scanning signal line G2L and having a source electrode connected to the pixel electrode E2, a capacitance electrode E3 connected to a drain electrode of the transistor T3, and a capacitance Ccs3 formed by the capacitance electrode E3 and the holding capacitance line CS2. In this configuration, when the scanning signal line GL becomes in a selection state, a potential of the pixel electrode E1 in the first sub-pixel portion 97 and a potential of the pixel electrode E2 in the second sub-pixel portion 98 become equal. Thereafter, when the second scanning signal line G2L becomes in a selection state, the transistor T3 becomes in an on state. Accordingly, a charge shifts between the pixel electrode E2 and the capacitance electrode E3, and the potential of the pixel electrode E2 varies. As a result, the potential of the pixel electrode E1 and the potential of the pixel electrode E2 become mutually different, and brightness of the first sub-pixel portion 97 and brightness of the second sub-pixel portion 98 become mutually different.